1. Field of Invention
The invention may relate to devices, systems, and/or methods for concentrating a liquid sample and to the detection, identification, and monitoring of submicron-sized particles in the concentrated sample such as, for example, viruses, virus-like agents, prions, viral subunits, viral cores of dilapidated viruses, etc.
2. Related Art
Detection and identification of viruses pathogenic to humans in an environment without limiting the detection and identification to a particular family, genus and species can be difficult, particularly in combat conditions such as, for example, a potential biological warfare (BW) threat environment. Instruments are needed which enable detection of, for example, remote releases of biological agents in a field environment, thereby providing early warning capabilities and allowing calculations for troop movements and wind patterns.
In the detection and monitoring of viruses, false positives associated with background materials can be a major obstacle. Background materials may include biological or other debris which obscures the detection of the viruses by registering as a virus when a sample is analyzed. Analysis of viruses requires a high degree of purification of those viruses to overcome background loading in order to avoid false positives. For example, a BW virus may be buried within loadings of other microorganisms which form biological debris having loading on a magnitude of 1010 larger than the threshold loading for the targeted virus itself.
Methods that culture viruses can often be used to increase the virus over background material. Culture methods, however, may be too slow for effective viral BW detection. Furthermore, some important viruses cannot be easily cultured.
Viruses may also be extracted from an environment and concentrated to an extent that permits detection and monitoring of viruses, without culturing procedures. Generally, in the detection of small amounts of viruses in environmental or biological liquids, it is necessary to both enrich the concentration of viruses many orders of magnitude (i.e., greatly reduce the volume of liquid solubilizing the viruses) and accomplish removal of non-viral impurities. In the presence of non-viral impurities, even the most sensitive detection methods generally require virus concentrations on the order of 10 femtomoles/microliter or more in the sampled liquid to reliably detect the viruses. In general, a standard method for the concentration of virus samples involves a tangential flow (cross-flow) filtration system to reduce the volume of the sample while removing impurities such as salts and small cellular debris. A more practical and effective device is needed, for example, for use with a capillary inlet of a gas-phase electrophoretic mobility molecular analysis (GEMMA) device.